Interface for dissimilarly braked vehicles

Abstract

Two different types of converter boxes (38, 84) provide the required interface for transmitting service brake control signals from the tractor unit (12) of a tractor-trailer combination vehicle to the trailer unit (16) thereof in which the tractor unit (17) and trailer unit (16) are provided with dissimilar braking systems. One type of converter box (38) provides the interface between a tractor (12) equipped with an electropneumatic braking system in which service brake applications are controlled by electrical signals and a conventional trailer (16) in which service brakes are controlled by pneumatic signals. The other type of converter box (84) provides the required interface between a tractor (12) which has service brakes controlled by conventional pneumatic signals and a trailer unit (16) which is provided with and electropneumatic braking system in which service brake applications are controlled by electrical signals.

I claim: 
     
       1. Interface converter box for converting a first type of brake control signal controlling the brakes of a tractor unit of a tractor-trailer combination vehicle to a second type of brake control signal controlling the brakes of a trailer unit of said combination vehicle, one of said first and second types of brake control signals comprising pneumatic braking signals and the other of said first and second types of brake control signals comprising electrical braking signals, said interface converter box including connecting means for receiving electrical power and said first type of brake control signals from the tractor unit and for transmitting said second type of brake control signals to said trailer unit, and converting means for converting said first type of brake control signals to the second type of brake control signals, said converting means including a trailer plug assembly for connection with the trailer unit and a receptacle for receiving a tractor plug assembly for connection with the tractor unit, said plug assemblies being connected by conductive means for transmitting electrical power from the tractor unit to the trailer unit through said interface convertor box, one of said plug assemblies being connectable to the unit having a braking system controlled by said electrical braking signals, said one plug assembly having a pair of offset portions, one of said offset portions carrying conductors transmitting electrical power, the other of said offset portions carrying conductors transmitting said electrical braking signals. 
     
     
       2. Interface convertor box for converting brake control signals as claimed in claim 1, wherein said tractor braking system is controlled by pneumatic braking signals and said trailer braking system is controlled by electrical braking signals, said converting means generating said electrical braking signals and causing the latter to vary as a function of the pneumatic braking signals. 
     
     
       3. Interface convertor box for converting brake control signals as claimed in claim 1, wherein said tractor braking system is controlled by electrical braking signals and said trailer braking system is controlled by pneumatic braking signals, said converting means generating said pneumatic braking signals and causing the latter to vary as a function of the electrical braking signals. 
     
     
       4. Interface convertor box for converting brake control signals as claimed in claim 1, wherein said tractor braking system is controlled by pneumatic braking signals and said trailer braking system is controlled by electrical braking signals, said converting means including a pressure transducer responsive to said pneumatic braking signals and generating an electrical signal which varies in accordance with said pneumatic braking signals. 
     
     
       5. Interface convertor box for converting brake control signals as claimed in claim 4, wherein said converting means includes a microprocessor for calculating said electrical braking signals, said microprocessor having an input receiving said electrical signal generated by said transducer. 
     
     
       6. Interface convertor box for converting brake control signals as claimed in claim 5, wherein said connecting means includes a pneumatic coupling for engagement with a corresponding coupling in the tractor braking system for communicating said pneumatic braking signals to said transducer. 
     
     
       7. Interface convertor box for converting brake control signals as claimed in claim 1, wherein said tractor braking system is controlled by electrical braking signals and said trailer braking system is controlled by pneumatic braking signals, said converting means including a proportional pressure modulating valve having an inlet receiving supply pneumatic pressure from said tractor braking system and an outlet for transmitting a variable pneumatic pressure level to said transmitting means. 
     
     
       8. Interface convertor box for converting brake control signals as claimed in claim 7, wherein said proportional pressure modulating valve includes a proportional solenoid actuator for generating a pressure level at said output which varies in accordance with said electrical braking signals. 
     
     
       9. Interface convertor box for converting brake control signals as claimed in claim 8, wherein said converting means further includes a pressure transducer for generating an electrical signal which varies as a function of the pressure level at the output of the proportional pressure modulating valve, and a microprocessor having a first input receiving said electrical braking signals, a second input receiving said signal from the transducer, and an output for transmitting a control signal to said solenoid actuator, said microprocessor being responsive to the signals at said first and second inputs to calculate said control signal. 
     
     
       10. Interface convertor box for converting brake control signals as claimed in claim 9, wherein said connecting means includes a pneumatic coupling for engagement with a corresponding coupling on the tractor for communicating said proportional pressure modulating valve with a pneumatic pressure source. 
     
     
       11. Interface convertor box for converting brake control signals as claimed in claim 1, wherein said converting means includes a pressure transducer for generating an electrical signal which varies in accordance with variations in the pressure level of the pneumatic braking signals. 
     
     
       12. Interface convertor box for converting brake control signals as claimed in claim 11, wherein said converting means includes a microprocessor receiving the electrical signal generated by said transducer. 
     
     
       13. Interface convertor box for converting brake control signals as claimed in claim 5, wherein said microprocessor is powered by the electrical power transmitted through said interface convertor box by said plugs and the conductive means. 
     
     
       14. Interface convertor box for converting brake control signals as claimed in claim 9, wherein said microprocessor is powered by the electrical power transmitted through said interface convertor box by said plugs and the conductive means. 
     
     
       15. Interfaced unit for converting brake control signals as claimed in claim 12, wherein said microprocessor is powered by the electrical power transmitted through said interface convertor box by said plugs and the conductive means.